Assessment of spatiotemporal trend of precipitation indices and meteorological drought characteristics in the Mahi River basin, India

Abstract

Understanding the trend and variability in hydroclimatic extremes as well as drought characteristics in the context of changing climate is of paramount importance in the management of watershed and rain-fed farming systems. This study focuses on understanding the variations in rainfall patterns & drought types with 3 regions of the agro-climatic zone, in the Mahi River basin, India. The basin is surrounded by three states i.e. Rajasthan, Madhya Pradesh, and Gujarat which is known for its substantial drought occurrences. Very limited studies have been carried out using agroclimatic indices. A 50 years of daily rainfall data (gridded, 0.25°×0.25° spatial resolution) from 1970 to 2019 has been taken from India Meteorological Department (IMD) to compute extreme precipitation indices using ClimPACT2 package and time series trend was tested by Mann-Kendall. Further, 51 grid points are divided into three regions (region 1, region 2, and region 3) as per the agro-climatic zones over the Mahi River basin. The region-wise agroclimatic rainfall variability has been analyzed using monthly standard deviation and anomaly index. The run theory was applied for the characterization of drought assessment. Standardized precipitation index (SPI) was performed for 3, 6, 12, and 24-months. The result found a Consecutive dry day (CDD) with increasing trend significantly and Consecutive wet days (CWD) with decreasing trend may cause a possible impact on agriculture. Findings revealed that region 2 recorded consequent frequent and maximum droughts events over the basin. Hence, the regional topography and moisture availability perform a major role in regional precipitation variability. The output of the current study would be utilized in a better understanding of the drought condition and give a better climate change indication at a regional-basin level. This finding may be valuable for researchers to find out the crucial agro-climatic regions in the basin for preparedness for effective management and planning of water resources.